Creating pdf files at runtime in c#

iTextSharp is no longer licensed under the MIT/LGPL license. Versions greater than 4.1.6 are licensed under the Affero GPL, meaning you can't even use it in a SaaS (Software as a Service) scenario without licensing your code under the GPL, or a GPL-compatible license.

Other opensource PDF implementations in native .NET include

• PDF Clown (make sure you get the patches to the latest version)
• PDFSharp
• PDFJet open source edition (commercial version also available, and you will need the JDK installed to build this)

There's also a couple of Java PDF libraries (like PDFBox) you can convert to .NET using IKVM.

iTextSharp http://itextsharp.sourceforge.net/

Complex but comprehensive.

itext7 former iTextSharp

Have a look at PDFSharp

It is open source and it is written in .NET, I use it myself for some PDF invoice generation.